A proposal for studying the relationship between the electro- encephalographic activity recorded epidurally over the cerebral cortex in crocodilians and the electrical activity of structures in the large subventricular mass which forms the bulk of the cerebral hemisphere in reptiles and is generally considered to be homologous with the basal ganglia of higher vertebrates. It will seek specifically to relate activity of these ganglia to changes in muscle tone and movement. The species to be studied is Caiman sclerops and the conditions will be in diving, pre-surfacing, and surfacing. The methods will include: simultaneous electroencephalographic recording from epidural and depth electrodes on the hypopallium and/or in various areas of the corpus striatum, recording of electromyograms from appropriate muscles simultaneously with EEG's; experimental stimulation of both cortex and basal ganglia while EEG recording is continued; and use of monamine depleting and enhancing drugs to attempt to relate the neurotransmitters of the basal ganglionic area to the electroencephalographic activity.